CN113848538A

CN113848538A - Dispersion spectrum laser radar system and measurement method

Info

Publication number: CN113848538A
Application number: CN202010593041.1A
Authority: CN
Inventors: 朱亮; 关健; 李国花; 闫敏
Original assignee: Shenzhen Oradar Technology Co Ltd
Current assignee: Shenzhen Oradar Technology Co Ltd
Priority date: 2020-06-25
Filing date: 2020-06-25
Publication date: 2021-12-28
Also published as: WO2021258709A1

Abstract

The invention discloses a dispersion spectrum laser radar system, comprising: an emitting end configured to emit a signal light beam; the receiving end comprises a receiving optical assembly and a dispersive spectrum photosensitive assembly, wherein the receiving optical assembly is used for receiving at least part of signal light beams reflected back by a target and part of environment light beams and transmitting the received signal light beams and part of environment light beams into the dispersive spectrum photosensitive assembly, and the dispersive spectrum photosensitive assembly disperses the incident light beams and distinguishes the light beams with different wavelengths on space; and the control and processor is used for controlling the dispersive spectrum photosensitive assembly to screen out the incident beam signals with the wavelength consistent with that of the signal light beams and calculating the flight time of photons based on the incident beam signals. The filtering of the signal light wavelength is realized through a dispersion mode, so that the signal-to-noise ratio and the measurement precision are improved.

Description

Dispersion spectrum laser radar system and measurement method

Technical Field

The invention relates to the technical field of optical sensors and laser radars, in particular to a dispersion spectrum laser radar system and a measurement method.

Background

The laser radar is an active three-dimensional measurement technology, a laser transmitting end transmits a laser beam to a space, a receiving end receives the laser beam reflected by an object, the received optical signal is processed to obtain the flight time of the laser beam in the space, and the distance and the direction information of a target can be calculated according to the relationship between the distance and the photon flight time as well as the speed of light. The ambient light interference is a problem generally faced by the existing laser radar system, namely when the laser radar works under outdoor strong light, the interference of solar ambient light is often caused, and the measured distance and the measurement precision are reduced to a certain extent.

In order to solve the problem of ambient light interference, a near-infrared laser emitter with relatively low solar spectral irradiance is often selected in the existing scheme, and then the receiving end is matched with a narrow-band filter near the waveband to perform further ambient light filtering. However, in consideration of practical problems in engineering, such as manufacturing tolerance of the center wavelength of the laser transmitter, manufacturing tolerance of the center transmission wavelength of the optical filter, drift of the center wavelength of the laser transmitter with temperature, and the like, the actually used optical filter has a spectral transmittance full width at half maximum which is much larger than the full width at half maximum of the laser wavelength, so that the effect of filtering ambient light is very limited, resulting in low signal-to-noise ratio and measurement accuracy.

The above background disclosure is only for the purpose of assisting understanding of the inventive concept and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above content is disclosed at the filing date of the present patent application.

Disclosure of Invention

The present invention is directed to a dispersive-spectrum lidar system and a measurement method thereof, which are used to solve at least one of the above-mentioned problems.

In order to achieve the above purpose, the technical solution of the embodiment of the present invention is realized as follows:

a dispersive-spectrum lidar system comprising: an emitting end configured to emit a signal light beam; the receiving end comprises a receiving optical assembly and a dispersive spectrum photosensitive assembly; the receiving optical assembly is used for receiving at least part of the signal light beam reflected back by the target and part of the ambient light beam and is incident into the dispersion spectrum photosensitive assembly, and the dispersion spectrum photosensitive assembly disperses the incident light beam so as to spatially distinguish the light beams with different wavelengths; and the control and processor is used for controlling the dispersive spectrum photosensitive assembly to screen out the incident beam signals with the wavelength consistent with that of the signal light beams and calculating the flight time of photons based on the incident beam signals.

In some implementations, the dispersive spectral photosensitive component includes a dispersive device and a photosensitive detector; the dispersion device is used for dispersing incident light beams and emitting the light beams at different angles according to the wavelength, so that the light beams with different wavelengths are incident on different spatial positions of the photosensitive detector.

In some implementations, the transmitting end includes a light source for emitting a signal light beam and modulated by the transmitting optical assembly for emission toward the target, and a transmitting optical assembly.

In some implementations, the signal light beam includes one of a spot light beam, a line light beam, and a flood light beam.

In some implementations, the transmitting end includes at least one transmitting channel and the receiving optical assembly includes at least one receiving channel; and the transmitting channels correspond to the receiving channels one to one.

In some implementations, the transmitting end and the receiving end are disposed in a coaxial formation.

In some implementations, the transmitting end and the receiving end are disposed off-axis.

In some implementations, the transmitting end and the receiving end are mounted on the same substrate.

In some implementations, the system further comprises a rotating platform for placing the transmitting end and the receiving end and rotating under the control of the control and processor to realize scanning.

The other technical scheme of the embodiment of the invention is as follows:

a method of making measurements using a dispersive spectroscopic lidar system, comprising the steps of:

emitting a signal light beam;

receiving at least a portion of the signal light beam reflected back by the target and a portion of the ambient light beam;

dispersing the received incident beams to spatially distinguish the beams of different wavelengths;

and screening out the incident beam signals with the wavelength consistent with that of the signal light beams, and calculating the flight time of photons based on the incident beam signals.

The technical scheme of the invention has the beneficial effects that:

aiming at the problem of ambient light interference in the laser radar, the invention provides a dispersion spectrum laser radar system based on dispersion and a measurement method, which can more efficiently reduce the influence of ambient light and improve the detection distance and precision of the laser radar.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic illustration of a dispersive-spectrum lidar assembly according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a mechanically scanned dispersive spectroscopic lidar system according to one embodiment of the present invention;

FIG. 3 is a schematic diagram of a non-mechanically scanned dispersive spectroscopic lidar system according to one embodiment of the present invention;

FIG. 4 is a schematic diagram of the components of a dispersive-spectrum lidar receiving end according to one embodiment of the present invention;

FIG. 5a is a schematic diagram of a waveguide transmission element according to one embodiment of the present invention;

FIG. 5b is a schematic diagram of a waveguide dispersive element according to one embodiment of the present invention;

FIG. 6 is a schematic diagram of a receiving end of a lidar system that includes an area-array dispersive spectroscopic assembly according to one embodiment of the present invention;

FIG. 7 is a schematic diagram of a receiving end of an area-array dispersive spectroscopy lidar in accordance with an embodiment of the present invention;

FIG. 8 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar in accordance with another embodiment of the present invention;

FIG. 9 is a schematic diagram of a receiving end of an area-array dispersive spectroscopy lidar in accordance with yet another embodiment of the present invention;

FIG. 10 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar in accordance with yet another embodiment of the present invention;

fig. 11 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar in accordance with yet another embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the embodiments of the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element. The connection may be for fixation or for circuit connection.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the embodiments of the present invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be in any way limiting of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

FIG. 1 is a schematic diagram of a dispersive-spectrum lidar system according to an embodiment of the present invention. The system 10 comprises a transmitting end 12, a receiving end 15 and a control and processor 11; wherein the emission end 12 comprises a light source 13 and an emission optical assembly 14; the receiving end 15 includes a dispersive spectrum sensing assembly 16 and a receiving optical assembly 17. The transmitting end 12 transmits a laser beam (also called signal light beam) with a specific wavelength range, such as laser beams with wavelengths around 960nm and 1550nm, through the light source 13, and the laser beam group is modulated by the transmitting optical component 14 and then transmitted to a target space; the receiving optical assembly 17 in the receiving end 15 is configured to collect at least a part of the laser beam reflected by the object in the target space and other beams from the ambient light, and to inject the collected laser beam and other beams into the dispersive spectrum photosensitive assembly 16, and the dispersive spectrum photosensitive assembly 16 disperses the received laser beam to spatially distinguish the incident laser beam according to different wavelengths; the spatial positions where the light beams with different wavelengths fall are different, the control and processor 11 controls the dispersive spectrum photosensitive component 16 and screens out an incident light beam signal only consistent with the central wavelength of the signal light beam emitted by the emission end 12 (specifically, a narrow-band wavelength light beam signal in a minimum interval range with the central wavelength of the emitted signal light beam as the center, theoretically, this interval range should include most signal light beams and a very small number of ambient light beams), and calculates the flight time of photons based on the incident light beam signal, and further calculates the distance D of the target according to the flight time, that is:

D＝c·t/2 (1)

where c is the speed of light and t is the time of flight.

Preferably, the dispersive spectrum photosensitive assembly 16 includes a dispersive device and a photosensitive detector, wherein the dispersive device disperses the incident light beam and emits the light beam at different angles according to the wavelength, so that the light beam with different wavelength is incident on different spatial positions of the photosensitive detector, thereby facilitating the subsequent screening. Specific embodiments of the dispersive-spectrum sensing assembly 16 will be described in detail later.

The dispersion function through dispersion spectrum sensitization subassembly makes incident beam distinguish according to the wavelength in the space to select signal light, compare with only filtering through the light filter, the signal light is gone out in the location that the dispersion can be very accurate, and the bandwidth of the narrowband light beam of selecting is compared in the bandwidth of light filter littleer, can filter the ambient light noise of the overwhelming majority simultaneously, promotes laser radar system's precision and SNR from this by a wide margin.

The system can be designed into different modes according to the requirements of the function, the performance and the like of different laser radars. For example, for a long-distance laser radar, the transmitting end 12 transmits a high-power laser beam, the laser beam is modulated into a spot, a line or the like in advance, and the angle of view covered by the whole laser beam is relatively small; for short-range lidar, the transmitting end 12 may be configured to emit a low-power laser beam with a certain field angle, which may be in the shape of floodlight, spots, lines, etc. Likewise, the receiving end 15 is also specially designed to correspond to the transmitting end. Several specific embodiments will be described in detail later.

In one embodiment, the emitting end 12 is configured to emit a single laser beam 18 into space, the laser beam 18 having a cross-sectional shape 20, such as a circular spot, an oval, a line, or the like. Accordingly, the receiving beam assembly 17 in the receiving end 15 is used to collect the beams within a certain field angle 19, and the field angle 19 of the receiving end 15 is designed to correspond to the laser beam 18, so that the receiving end can collect the laser beam reflected from the object in the target space, thereby further calculating the flight time. Generally, the angle of view 19 is larger than the divergence angle of the laser beam 18. For convenience of description, in the embodiment of the present invention, one laser beam and a receiving end view angle corresponding to the laser beam are referred to as a channel, and transmitting channels of a transmitting end correspond to receiving channels of a receiving end one to one, so as to implement distance measurement on a target object. The channels may be any form of point channels, line channels, encoding channels, and the like.

While a single channel is schematically depicted in fig. 1, in other embodiments, the system 10 may implement distance measurements at larger field angles by scanning a single channel or multiple channels. For example, in one embodiment, the beam scanning device, such as a MEMS galvanometer, a mechanical turning mirror, etc., is disposed in the transmitting optical assembly 14 and/or the receiving optical assembly 17 to scan the beam, thereby implementing multi-channel measurement, although an additional beam scanning assembly may be added. In one embodiment, the transmitting end 12 can simultaneously emit a multi-channel laser beam, and correspondingly, the receiving end 15 also has a plurality of receiving channels corresponding to the transmitting channels of the transmitting end 12 one by one, so that multi-channel (e.g., dot matrix, linear array, etc.) scanning of the target can be simultaneously achieved.

In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in a coaxial manner, which can ensure a one-to-one correspondence between the transmitting channels and the receiving channels, for example, by adding optical elements such as a half mirror with reflection and transmission functions, a transmission mirror with an opening in the middle of the mirror, and the like. In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in an off-axis manner, compared with a coaxial manner, the off-axis requirement on hardware is low, the assembly is convenient, the disadvantage is that the problem of parallax needs to be considered, when the target is at different distances, the transmitting channel and the receiving channel can have deviation due to parallax, it can be understood that the problem of parallax can be ignored on the premise that the measured distance is far greater than the baseline distance between the transmitting end and the receiving end, and when the measured distance is close, the parallax problem can be solved by means of calibration, light spot positioning and the like.

In some embodiments, the transmitting terminal and the receiving terminal are mounted on the same substrate to facilitate miniaturization and integration of the system, for example, a laser light source and a photosensitive chip may be simultaneously manufactured on the same semiconductor substrate through a semiconductor process, and then optical devices, electronic components, and the like are further mounted on the semiconductor substrate to form the transmitting terminal and the receiving terminal.

In some embodiments, the dispersive spectroscopic lidar is configured as a mechanically scanned version of the lidar system, as shown in fig. 2, which includes a transmitting end 201, a receiving end 202, and a rotating platform 203 for positioning the transmitting end and the receiving end, the rotating platform 203 may be rotated in a certain direction 204 by rotating the assembly under the control of the control and processor 11 to achieve scanning of a large angular field of view (e.g., 360 degrees).

In some embodiments, the dispersive-spectrum lidar is configured as a non-mechanically scanned version of the lidar system, as shown in fig. 3, with the transmitting end 12 and the receiving end 15 configured to have a common field of view 31, and generally, the transmitting end 12 is configured to transmit multiple channels of laser beams outward to achieve illumination of targets within the common field of view, and the receiving end 15 is configured to collect the laser beams reflected back from within the common field of view.

Based on the dispersive spectrum lidar system explained in the embodiments, the embodiment of the invention also provides a method for measuring based on the dispersive spectrum lidar, which comprises the following steps:

firstly, emitting a signal light beam;

secondly, receiving at least part of the signal light beam reflected back by the target and part of the ambient light beam;

thirdly, dispersing the received incident beams to spatially distinguish the beams with different wavelengths;

and finally, screening out the incident beam signals with the wavelength consistent with that of the signal light beams, and calculating the flight time of photons based on the incident beam signals.

The above steps are specifically implemented by using the dispersive-spectrum lidar system in the embodiment shown in fig. 1 to 3, and the detailed method steps can refer to the description in the embodiment shown in fig. 1 to 3, which is not described herein again.

Fig. 4 is a schematic diagram of the composition of a dispersive-spectrum lidar receiving end according to one embodiment of the invention. The receiving end comprises a dispersive spectrum photosensitive assembly 41 and a receiving optical assembly 42; the receiving optical assembly 42 is composed of at least one lens or a lens array, and is used for receiving a portion of the laser beam (signal light) reflected by the object 46 in the target space and other ambient light beams from the environment, in this embodiment, a bar-shaped laser beam is emitted from the emitting end as an example, it is understood that the present invention is not limited to the bar-shaped beam, and the object 46 reflects the bar-shaped beam 47 (including the signal light and the ambient light) and is collected by the receiving optical assembly 42 and incident on the dispersive spectrum sensing assembly 41.

The dispersive spectrum photosensitive assembly 41 comprises a diaphragm 415, a collimating device 414, an optical filter 413, a dispersive device 412 and an array detector 411 which are sequentially arranged along an incident light path; the light beam 47 reflected by the object 46 passes through the receiving optical assembly 42 and then converges on the plane of the diaphragm 415; the aperture limits the angle of view of the receiving optical assembly 42, only the reflected beam received in this angle of view can pass through the aperture and further impinge on the collimating device 414; the collimating device 414 collimates the reflected beam transmitted through the diaphragm into a parallel beam, which is then incident on the filter 413; the optical filter 413 is a band-pass filter for filtering the incident light beam and allowing only a narrow-band wavelength light beam within a certain bandwidth range to pass through, with the central wavelength of the signal light as the center; generally, the passband wavelength of the filter 413 is set to be centered at the signal light center wavelength, and the transmittance full width at half maximum is typically several tens of nanometers (as an example only), but since the full width at half maximum of the signal light is much narrower than the bandwidth of the filter, most of the signal light and the ambient light of the ambient light, which is several tens of nanometers near the signal light center wavelength, will pass through the filter.

The narrow-band wavelength light beam emitted from the filter 413 enters the dispersion device 412, and the dispersion device 412 disperses the incident narrow-band wavelength light beam in one direction according to the wavelength, so that light with different wavelengths is irradiated to different positions on the surface of the array detector 411, for example, a plurality of light beams 43, 44, 45 arranged along the wavelength are formed on the surface of the array detector 411. Thus, a part of the pixels (e.g. 44) of the array detector 411 are only irradiated by the signal light and the ambient light with the same wavelength as the signal light, and the ambient light with the different wavelength from the signal light will not overlap with the signal light in space, e.g. 43, 45, and then the control and processor can read out only the signal in the corresponding pixel of the signal light band array detector 411 and calculate the time of flight of the photon based on the read-out light signal, and further can calculate the distance of the target according to the time of flight. The dispersion is distinguished in space, so that the ambient light from the light beam with the optical filter narrow-band wavelength can be further filtered, and only the light beam within the signal light bandwidth range can be theoretically screened out through the reasonable design of the dispersion device and the design of the array detector, so that compared with the filtering effect of only the optical filter, the noise from the ambient light can be further greatly reduced, the suppression effect on the ambient light is finally realized, and the measurement precision and the signal to noise ratio are improved.

The diaphragm 415 is generally disposed on the focal plane of the receiving optical assembly 42, and the diaphragm 415 includes at least one hole or one slit, and the arrangement form and number of the holes or slits determine the optical performance, such as the field angle and the resolution, of the dispersive spectrum photosensitive assembly 41; generally, the diaphragm is set to a reasonable form according to the overall performance requirement of the laser radar system, for example, for a single-channel laser radar, if a line beam is emitted from the transmitting end, the diaphragm may only contain a single linear hole, i.e. a single-slit diaphragm; if the emission end emits a punctiform light beam, the diaphragm may comprise only a single circular hole, i.e. a single aperture diaphragm. When the transmitting end emits a planar light beam, the aperture may include a plurality of slits or a plurality of holes arranged in an array, that is, a multi-slit aperture or a multi-hole aperture, so that the array light signal may be synchronously received to obtain depth measurement information of the array, which will be described in detail later.

The position of the diaphragm light-passing hole or the slit can be fixed or movable in the plane of the diaphragm, and when the position of the diaphragm light-passing hole or the slit is movable, the moving amount of the position of the light-passing hole or the slit is controlled by the control and processor. The movable diaphragm includes but is not limited to being implemented by a MEMS mechanism, a liquid crystal device, and the like. In one embodiment, the opening and closing of the light-passing hole or slit of the diaphragm can also be controlled by the control and processor. For a multi-aperture or multi-slit diaphragm, the apertures or slits on the diaphragm can be arranged in a one-dimensional arrangement or a two-dimensional arrangement, such as a regular two-dimensional array, an irregular two-dimensional array, etc., as required.

In some embodiments, the array detector 411 is an array type optical receiving device composed of a plurality of pixels, typically an APD (avalanche photo diode) array and an SPAD (single photon avalanche diode) array. The array detector is capable of measuring the time of flight of the signal light reflected from the target back to the array detector. The pixels on the array detector comprise at least one column of pixels in a direction coincident with the direction of dispersion.

In some embodiments, the collimating device may be formed by one or more of a combination of at least one lens, a microlens array, a mirror (including various types of mirrors, including a flat mirror, a curved mirror, a reflecting prism, etc.), and a waveguide transmission element.

Referring to fig. 5a, fig. 5a is a schematic diagram of a waveguide transmission element according to an embodiment of the present invention, the waveguide transmission element is composed of an incident coupler 51, a waveguide 52 and an exit coupler 53, and is used for transmitting an incident light beam in a three-dimensional space and emitting the incident light beam outward in a certain direction at a suitable position, and the waveguide transmission element can make the function of a collimating device more extensive, for example, the spatial position and the emitting direction of an exit collimated light beam can be controlled as required, which will be described later. The waveguides 52 in the waveguide transmission element may be optical fibers. The waveguide is capable of transmitting a light beam in a curved path in three dimensions. The input coupler 51, the output coupler 53 and the waveguide 52 may be separate off-chip devices, may be implemented as an on-chip optical circuit, or may be a combination of an on-chip device and a separate off-chip device.

In some embodiments, the filter 413 may be placed at other locations in the optical path, such as outside the aperture 415 (including between the receiving optical component 42 and the target object 46, or between the aperture 415 and the receiving optical component 42), or between the aperture 415 and the collimating device 414, or between the collimating device 414 and the dispersive device 412, or between the dispersive device 412 and the array detector 411; preferably, the filter 413 is placed between the collimating device 414 and the dispersing device 412.

The dispersive device 412 includes at least one dispersive element, such as one or more of a prism, a grating, and a dispersive hologram, which can form the outgoing beams with different outgoing angles for the incoming beams at different wavelengths, thereby achieving the dispersive effect on the beams. The dispersion hologram is a hologram device having both a dispersion function and a convergence function (or a divergence function). In some embodiments, the dispersive device 412 includes, in addition to the dispersive elements, a combination of one or more of lenses, lens groups, microlens arrays, mirrors.

In some embodiments, the dispersive element may also be a waveguide dispersive element, as shown in fig. 5 b. The waveguide dispersive element comprises an input coupler 54, a beam splitter 56, a beam combiner 57, an output coupler 58 and a waveguide 55. The incident light from the waveguide dispersive element is coupled via an input coupler 54 into a single waveguide 55, the other end of which is connected to a beam splitter 56. The beam splitter 56 distributes its incident light in equal intensity or unequal intensity, equal phase, into a plurality of waveguides connected between the beam splitter 56 and the beam combiner 57, illustrated for convenience of description as N waveguides whose lengths are incremented by a fixed increment. The number of N needs to be designed according to the dispersion resolution of the waveguide dispersive element. Generally, the larger the value of N, the higher the dispersion resolution of the waveguide dispersive element. Due to the fact that the length of the N waveguides is increased, constant phase difference exists between emergent light of the N waveguides; however, the effective refractive indexes of the waveguides to the light waves with different wavelengths are different, and the phase difference formed by the light waves with different wavelengths after passing through the N waveguides is different. Therefore, the positions at which the light of different wavelengths constructively interfere in the beam combiner 57 are different. In the beam combiner, the position of the constructive interference of the optical waves with the central wavelength of the signal light is selected, and the position is connected with the emergent coupler 58 by adopting a waveguide, so that the signal light and the environment light (namely the light beam with the central wavelength consistent with the signal light) with the wavelength similar to that of the signal light can be led out from the beam combiner 57.

In some embodiments, the waveguides 55 in the waveguide dispersive element may be optical fibers. The waveguide is capable of transmitting a light beam in a curved path in three dimensions. The beam splitter 56, the input coupler 54, the beam combiner 57, the output coupler 58 and the waveguide 55 may be separate off-chip devices, may be implemented as an on-chip optical path, or may be a combination of an on-chip device and a separate off-chip device.

In the above embodiment, the dispersive spectrum photosensitive component capable of achieving single-channel measurement is taken as an example for explanation, however, in some other applications, a laser radar system is often required to achieve multi-channel measurement synchronously to obtain measurement with a large field angle and a higher resolution, and in the following embodiment, an area array dispersive spectrum laser radar including an area array dispersive spectrum photosensitive component capable of achieving multi-channel measurement is provided. The contents of the dispersive spectroscopic photosensitive assembly described above are also applicable to the area array dispersive spectroscopic photosensitive assembly described in each of the embodiments below.

Fig. 6 is a schematic diagram of a receiving end of a laser radar system including an area-array dispersive spectroscopic photosensitive assembly according to an embodiment of the present invention, the receiving end includes an area-array dispersive spectroscopic photosensitive assembly 61 and a receiving optical assembly 62, wherein the receiving optical assembly 62 is composed of at least one lens or lens array for collecting a portion of laser beams (signal light) reflected by an object in a target space and other ambient light beams from the environment, such as reflected

beams

631, 632, and 633 from different field areas (different channels) in a field of view, and the reflected beams are collected by the receiving optical assembly 62 and incident on the area-array dispersive spectroscopic photosensitive assembly 61. The area array dispersive spectrum photosensitive assembly 61 comprises an area array diaphragm 615, a collimating device 614, a filter 613, a dispersive device 612 and an area array detector 611 which are sequentially arranged along an incident light path.

The area array diaphragm 615 is provided with a plurality of holes or slits arranged in an area array, each hole or slit is used for receiving the light beam in the corresponding incident angle of view of the receiving optical assembly 62, for example, 3 holes or slits are schematically shown in fig. 6 for receiving the incident light beams 631, 632, and 633 coming from three different directions, and for convenience of illustration, only three channels are taken as an example, but it is not understood that the three channels are limited to only three channels. The number and arrangement of the apertures or slits in the area array stop 615 determine the field angle and imaging resolution of the entire photosensitive assembly 61. Each light beam passing through the area array diaphragm 615 is further incident to the collimating device 614; the collimating device 614 collimates the light beam transmitted through the diaphragm into a multi-channel parallel light beam, which is then incident on the filter 613; the filter 613 is a band pass filter, and is configured to filter an incident light beam and allow only a narrow-band wavelength light beam within a certain bandwidth centered on the center wavelength of the signal light to pass therethrough. The narrow-band wavelength light beam emitted from the filter 613 is incident on the dispersion device 612, and the dispersion device 612 disperses the incident narrow-band wavelength light beam in at least one direction according to the wavelength, so that the light with different wavelengths is irradiated to different positions on the surface of the area array detector 611, for example, a plurality of light beams a, b, and c (only three light beams are taken as an example, and actually, more light beams may be formed) arranged along the wavelength are formed on the surface of the area array detector 611. The area array detector 611 includes a plurality of pixels 616 (e.g., pixels such as APD and SPAD) arranged in a two-dimensional area array, generally, the total number of pixels is greater than the total number of apertures or slits on the area array diaphragm, and it is preferable to separately provide a corresponding pixel group for each aperture or slit on the area array detector 611, where each pixel group is spatially independent for receiving the light beams transmitted from the aperture or slit of the corresponding diaphragm. Due to the dispersion, the light beams a, b and c with different wavelengths will be incident to different positions in the pixel group, if the wavelength of the b light beam is consistent with the wavelength of the signal light, the signal generated by the pixel for receiving the b light beam will be read out by the control and processor, and the flight time of the photon is calculated based on the read-out light signal, further the distance of the target can be calculated according to the flight time. Because the ambient light of other wave bands is filtered, the noise from the ambient light is greatly reduced, the effect of inhibiting the ambient light is finally realized, and the measurement precision is improved.

In some embodiments, the collimating device 614 may be formed by one or more of a combination of at least one lens, a microlens array, a mirror (including various types of mirrors such as a flat mirror, a curved mirror, a reflecting prism, etc.), and an area array waveguide transmission element.

In some embodiments, the dispersive device 612 comprises a dispersive element, wherein the dispersive element may be a combination of one or more of a prism, a grating, a dispersive hologram. The dispersive device 612 may also include a converging lens, which may be made up of one or more combinations of at least one lens, a microlens array, a mirror.

In some embodiments, the dispersive device 612 may also be an area-array waveguide dispersive element, which is composed of a plurality of waveguide dispersive elements arranged as shown in fig. 5a and 5b, and each waveguide dispersive element in the area-array waveguide dispersive element is respectively corresponding to a hole or a slot on the diaphragm, and is respectively used for receiving the light beam transmitted from the corresponding hole or slot.

For the area array dispersion spectrum laser radar, in order to enable a laser radar system to achieve better performance, a straight device and a dispersion device need to be integrally considered to design a corresponding area array dispersion spectrum laser radar receiving end, and several receiving end embodiments are proposed according to the main idea of the invention.

Fig. 7 is a schematic diagram of a receiving end of an area-array dispersive spectroscopy lidar in accordance with an embodiment of the present invention. The receiving end comprises an area array dispersion spectrum photosensitive assembly 71 and a receiving optical assembly 72; therein, the receiving optical assembly 72 is composed of at least one lens or lens array for collecting the part of the laser beam (signal light) reflected by the object in the target space and other ambient light beams from the environment, such as the reflected

beams

731, 732 and 733 from different field regions (different channels) in the field of view, which are collected by the receiving optical assembly 72 and incident into the area-array dispersive spectrum photosensitive assembly 71. The dispersive spectrum photosensitive assembly 71 comprises an area array diaphragm 715, a first microlens array 714, an optical filter 713, a dispersive device 712 and an area array detector 711.

The area array diaphragm 715 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used for receiving the light beam in the corresponding incident angle of view (channel) of the receiving optical assembly 72 corresponding to the hole or slit. Each light beam passing through the area array diaphragm 715 is further incident on the first microlens array 714; each microlens in the first microlens array 714 corresponds to a hole or a slit in the area array diaphragm 715 one by one, and respectively collimates the light beam passing through the diaphragm into parallel light beams, and the parallel light beams are then incident on the optical filter 713; the optical filter 713 transmits a narrow-band wavelength beam in a certain bandwidth range centered on the center wavelength of the signal light, and the transmitted narrow-band wavelength beam is then incident on the dispersion device 712. The dispersive device 712 includes a dispersive element 717, which may be a combination of one or more of a prism, a grating, and a dispersive hologram, and a second microlens array 716, for dispersing the incident narrow band wavelength beam in at least one direction by wavelength; each microlens in the second microlens array 716 corresponds to each microlens in the first microlens array 714 or a hole or slit in the area array diaphragm 715, and is used for converging/focusing the light beam from the dispersive element 717 to be incident on the corresponding pixel on the area array detector 711. Due to the dispersion effect of the dispersion element 717, the light beams from the same diaphragm are made to be incident on different pixels according to different wavelengths, so that the light beams are spatially separated, and finally, the pixel signals of the light beams which are consistent with the wavelength of the signal light are read out by the control and processor.

Fig. 8 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar in accordance with another embodiment of the present invention. The receiving end comprises an area array dispersion spectrum photosensitive assembly 81 and a receiving optical assembly 82; here, the receiving optical assembly 82 is composed of at least one lens or lens array, and is used to collect a portion of the laser beam (signal light) reflected by the object in the target space and other ambient light beams from the environment, such as reflected beams from different field areas (different channels) in the field of view, for convenience of illustration, only the channel 831 is taken as an example in the present embodiment, and the reflected beams are collected by the receiving optical assembly 82 and incident on the area-array dispersive spectrum sensing assembly 81. The dispersive spectrum photosensitive assembly 81 comprises an area array diaphragm 815, a first microlens array 814, a filter 813, a dispersive device 812 and an area array detector 811.

Unlike the embodiment shown in fig. 7, the dispersive device 812 in the embodiment shown in fig. 8 includes a second microlens array 819, a first lens 818, a dispersive element 817, and a second lens 816, which are arranged in this order along the optical path. Each microlens in the second microlens array 819 corresponds to each microlens in the first microlens array 814 or a hole or a slit in the area array diaphragm 815 one by one, and is used for receiving and converging collimated light beams collimated by the first microlens array 814; the first lens 818 receives the converged light beams from the second microlens array 819, collimates and expands the light beams, the expanded parallel light beams are incident on the dispersion element 817 and then are incident on the second lens 816 after being dispersed, and the second lens 816 is used for converging or focusing the dispersed light beams so as to be incident on corresponding pixels on the area array detector 811. Due to the dispersion action of the dispersion element 817, the light beams with different wavelengths are incident to the second lens 816 in different directions, so that the light beams from the same diaphragm are incident to different pixels according to different wavelengths, and are separated in space, and finally, pixel signals of the light beams which are consistent with the wavelength of the signal light are received and are subsequently controlled and read by a processor. The first lens 818 and the second lens 816 may be single lenses or lens groups composed of multiple lenses.

Fig. 9 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar in accordance with yet another embodiment of the present invention. The receiving end comprises an area array dispersive spectrum photosensitive assembly 91 and a receiving optical assembly 92. Therein, the receiving optical assembly 92 is composed of at least one lens or lens array for collecting a part of the laser beam (signal light) reflected by the object in the target space and other ambient light beams from the environment, such as reflected

beams

931, 932 and 933 from different field regions (different channels) in the field of view, the reflected beams are collected by the receiving optical assembly 92 and incident into the area-array dispersive spectrum photosensitive assembly 91. The dispersive spectrum photosensitive assembly 91 comprises an area array diaphragm 915, a first micro lens array 914, an optical filter 913, a dispersive device 912 and an area array detector 911.

Unlike the embodiments shown in fig. 7 and 8, the dispersive device 912 in the embodiment of fig. 9 includes an area array waveguide dispersive element 912 composed of a plurality of waveguide dispersive elements 916, wherein each waveguide dispersive element 916 is used to receive the light beam from the corresponding aperture or slit, and selectively output the light beam with the same central wavelength as the signal light to be incident on the corresponding pixel of the area array detector 911. Generally, each waveguide dispersive element 916 on the area array waveguide dispersive element 912 has a one-to-one correspondence, including a one-to-one correspondence in number and/or arrangement, with each microlens on the first microlens array 914 or with each aperture or slit on the stop 915.

In the embodiments shown in fig. 7 to 9, the collimating devices are microlens arrays, and other devices such as lenses (lens groups), waveguide transmission elements, and the like can be used. Two specific embodiments will be exemplarily described below.

Referring to fig. 10, fig. 10 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar according to yet another embodiment of the present invention. The receiving end comprises an area-array dispersive spectrum photosensitive assembly 101 and a receiving optical assembly 102. The dispersive spectrum photosensitive assembly 101 includes an area array diaphragm 1015, a first lens 1014, a filter 1013, a dispersive device 1012, and an area array detector 1011.

The area array aperture 1015 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used for receiving the light beam in the corresponding incident angle of view of the corresponding receiving optical assembly 102. Each light beam passing through the area array diaphragm 1015 is further incident on the first lens 1014, and the first lens 1014 collimates the light beam transmitted through the diaphragm into a parallel light beam, which is then incident on the filter 1013; the filter 1013 transmits a narrow-band wavelength light beam in a certain bandwidth range centered on the center wavelength of the signal light, and the transmitted narrow-band wavelength light beam is then incident on the dispersion device 1012. The dispersive device 1012 comprises a dispersive element 1017 and a second lens 1016, the dispersive element 1017 is used for dispersing the incident narrow band wavelength light beam along at least one direction according to the wavelength; the second lens 1016, in cooperation with the first lens 1014, converges/focuses the incident parallel light beams to be incident on corresponding pixels on the area array detector 1011. Due to the dispersion effect of the dispersion element 1017, the light beams from the same diaphragm are made to be incident on different pixels according to different wavelengths, so that the light beams are separated in space, and finally, the pixel signals of the light beams which are consistent with the wavelength of the signal light are received and are subsequently read by the control and processor. The first lens 1014 and the second lens 1016 may be single-lens lenses or lens groups composed of multiple lenses.

Referring to fig. 11, fig. 11 is a schematic diagram of a receiving end of an area-array dispersive spectroscopic lidar according to yet another embodiment of the present invention. The receiving end comprises an area array dispersion spectrum photosensitive assembly 111 and a receiving optical assembly 112; the dispersive spectrum photosensitive assembly 111 comprises an area array diaphragm 1115, a collimating device 1114, a filter 1113, a dispersive device 1112 and an area array detector 1111.

The area array diaphragm 1115 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used for receiving the light beam in the corresponding incident angle of view of the corresponding receiving optical assembly 112. Each light beam passing through the area array diaphragm 1115 is further incident on the collimating device 1114, the collimating device 1114 comprises an area array waveguide transmission element composed of a plurality of waveguide transmission elements 117, wherein each waveguide transmission element 117 is used for receiving the light beam from a corresponding diaphragm hole or slit, transmitting and collimating the light beam and then emitting the light beam. Generally, each waveguide transmission element 117 of the area array waveguide transmission element is in one-to-one correspondence with each hole or slot of the stop 1115, where the one-to-one correspondence includes one-to-one correspondence in number and/or arrangement. In one embodiment, the collimating device 1114 further includes a lens, such as the first microlens array 116 and/or the second microlens array 118, disposed at the input-coupler and/or output-coupler end of each waveguide transmission element, with each microlens in the microlens array corresponding one-to-one to each waveguide transmission element.

The parallel light beams collimated by the collimating device 1114 are then incident on the optical filter 1113; the filter 1113 transmits a narrow-band wavelength beam within a certain bandwidth range centered on the center wavelength of the signal light, and the transmitted narrow-band wavelength beam is then incident on the dispersion device 1112. The dispersive device 1112 comprises a dispersive element 115 and a third microlens array 114, the dispersive element 115 is used for dispersing the incident narrow-band wavelength light beam in at least one direction according to the wavelength; each microlens in the third microlens array 114 corresponds to a respective aperture or slit on a respective waveguide transmission element 117 and/or stop 1115 in the area array waveguide transmission element, and is used for converging/focusing the light beams from the dispersive element 115 to be incident on a corresponding pixel on the area array detector 1111.

In the embodiment shown in fig. 9, an area array waveguide dispersive element is adopted in the dispersive element in the dispersive spectrum photosensitive assembly, in the embodiment illustrated in fig. 11, the collimating device employs an area array waveguide transmission element, since the waveguide is capable of transmitting light beams in a curved path in three dimensions, the multiple exit couplers in an area array waveguide dispersive (transmission) element can be spatially rearranged or directionally adjusted, the spatial arrangement of the plurality of input couplers may be rearranged to achieve a desired arrangement and/or direction of the outgoing light beam for the system, for example, for the arrangement of pixels on an area array detector, for more uniformly directing the light beam in each aperture onto the corresponding pixel, the arrangement and/or orientation of the exit couplers may be readjusted to achieve flexible configuration of the mapping relationship between the aperture and the detector pixels.

It is understood that any device having the same function as the collimator device may be used in the dispersive spectrum photosensitive assembly instead of the collimator device, and similarly, any device having the same function as the dispersive element may also be used in place of the dispersive element, and the combination manner of the collimator device and the dispersive element is not limited to the above embodiments, and any combination which is based on the idea of the present invention and can achieve the similar function is within the protection scope of the present invention.

As will be described later on with reference to fig. 1, the transmitting end 12 comprises a light source 13 and a transmitting optical assembly 14 for transmitting at least one channel of laser light beams (signal light beams) into space, and can be configured in different forms for different application needs.

In some embodiments, the emitting end is used for emitting a spot light beam, which may be a single-point light spot or a multi-point light spot, and in order to obtain point cloud data with high spatial resolution in the measurement field of view, a scanning element may be added to the emitting optical assembly 14 in one embodiment; in addition, beam shaping elements, such as lenses, mirrors, etc., are included in the emission optical assembly 14 for shaping the diverging light beam emitted by the light source into a single or multi-point spot and impinging on the target. It can be understood that, when the transmitting end only transmits one point light spot, the corresponding diaphragm in the receiving end only needs one light through hole, and the light through hole is located on the optical axis of the receiving system; when the reflecting end emits a plurality of point light spots, the diaphragm is provided with a plurality of light through holes, and each light through hole and each emitted point light spot form a one-to-one corresponding relationship. For the multi-spot light spots, the multi-spot light spots can be arranged along a line, and can also be two-dimensionally arranged along the x direction and the y direction.

In some embodiments, the transmitting end is used to transmit a single line spot or a multi-line spot, and also to obtain high spatial resolution point cloud data over the field of view of the measurement, a scanning element may be added to the transmitting optical assembly 14 in one embodiment. Also included in the transmit optical assembly 14 are beam shaping elements, such as lenses, mirrors, etc., for shaping the diverging beam emitted by the light source into a single or multi-line spot that is directed onto a target. Generally, the linear light spot has a small beam divergence angle, for example, 0.05 to 0.15 ° in one direction, and reaches a light spot of several tens of degrees in the other direction. When the emitted spot is a multi-line spot, the lines are parallel to each other.

In the embodiments of the point light spot and the line light spot, the light source at the emitting end may be a single-point edge emitting laser, a single-point vertical cavity surface laser (VCSEL), a emitting laser array composed of multiple edge emitting lasers, a VCSEL array, a VCSEL with controllable division, and the like. The beam shaping device is composed of one or more of lens, microlens array, Metasource device, beam splitter prism and reflector. The scanning element may be comprised of a MEMS micromirror, a rotating prism pair, a mechanical galvanometer, an OPA scanning device, or the like.

In some embodiments, the emission end may directly emit a multi-point light spot without passing through a scanning element, the emission end includes an area array light source composed of a plurality of sub light sources and an emission optical assembly, divergent light beams emitted by the sub light sources are shaped into a point light spot or a line light spot by a light beam shaping element in the emission optical assembly to be emitted into space, the processing and controller may illuminate a plurality of sub sources in the area array light source in a partitioned manner, and only gate corresponding pixels on the receiving end detector when the sub light sources in the corresponding area are illuminated, so as to implement scanning measurement along at least one direction. The light source may be a plurality of edge emitting lasers that can be turned on one by one, a plurality of VCSEL lasers that can be turned on one by one, a VCSEL area array laser that can be turned on in a divided manner, or the like.

It will be understood that the nature of the system of the present invention, when subject to corresponding structural or component changes or simple substitutions in position or hardware to suit the needs, still employs the dispersive-spectrum lidar of the present invention and is therefore considered to be within the scope of the present invention.

It is to be understood that the foregoing is a more detailed description of the invention, and that specific embodiments are not to be considered as limiting the invention. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention. In the description herein, references to the description of the term "one embodiment," "some embodiments," "preferred embodiments," "an example," "a specific example," or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention.

In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. One of ordinary skill in the art will readily appreciate that the above-disclosed, presently existing or later to be developed, processes, machines, manufacture, compositions of matter, means, methods, or steps, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. A dispersive-spectrum lidar system, comprising:

an emitting end configured to emit a signal light beam;

the receiving end comprises a receiving optical assembly and a dispersive spectrum photosensitive assembly; the receiving optical assembly is used for receiving at least part of the signal light beam reflected back by the target and part of the ambient light beam and is incident into the dispersion spectrum photosensitive assembly, and the dispersion spectrum photosensitive assembly disperses the incident light beam so as to spatially distinguish the light beams with different wavelengths;

and the control and processor is used for controlling the dispersive spectrum photosensitive assembly to screen out the incident beam signals with the wavelength consistent with that of the signal light beams and calculating the flight time of photons based on the incident beam signals.

2. The dispersive-spectrum lidar system of claim 1, wherein: the dispersive spectrum photosensitive assembly comprises a dispersive device and a photosensitive detector; the dispersion device is used for dispersing incident light beams and emitting the light beams at different angles according to the wavelength, so that the light beams with different wavelengths are incident on different spatial positions of the photosensitive detector.

3. The dispersive-spectrum lidar system of claim 1, wherein: the transmitting end comprises a light source and a transmitting optical component, wherein the light source is used for transmitting a signal light beam, and the signal light beam is modulated by the transmitting optical component and then is transmitted to the target.

4. The dispersive-spectrum lidar system of claim 1, wherein: the signal light beam comprises one of a spot light beam, a line light beam and a flood light beam.

5. The dispersive-spectrum lidar system of claim 1, wherein: the transmitting end comprises at least one transmitting channel, and the receiving optical assembly comprises at least one receiving channel; and the transmitting channels correspond to the receiving channels one to one.

6. The dispersive-spectrum lidar system of claim 1, wherein: the transmitting end and the receiving end are arranged in a coaxial form.

7. The dispersive-spectrum lidar system of claim 1, wherein: the transmitting end and the receiving end are arranged in an off-axis mode.

8. The dispersive-spectrum lidar system of claim 1, wherein: the transmitting end and the receiving end are mounted on the same substrate.

9. The dispersive-spectrum lidar system of claim 1, wherein: the device also comprises a rotating platform which is used for placing the transmitting end and the receiving end and rotates under the control of the control and processor to realize scanning.

10. A method of making measurements using a dispersive spectroscopic lidar system, comprising the steps of:

emitting a signal light beam;